What is a ground glass nodule?

A ground glass nodule (GGN) is a type of lung nodule seen on CT scans. It appears as an area of hazy or cloudy opacity in the lung tissue that allows some but not all light to pass through it. The term "ground glass" refers to the frosted or semi-transparent appearance of the nodule.

GGNs can have different sizes and shapes, and they can be solitary or multiple. They may represent a variety of benign or malignant conditions, including infectious or inflammatory processes, granulomatous diseases, and various types of lung cancer.

In general, solid and irregular-shaped GGNs are more likely to be malignant, whereas pure or part-solid GGNs are more indicative of benign or early-stage lung cancer. However, a biopsy or follow-up imaging tests are necessary to rule out cancer and determine the appropriate treatment plan.

GGNs are usually closely monitored with repeated CT scans to detect any changes that may indicate the need for further investigation or treatment. They may also be biopsied using various techniques, including needle biopsy or surgical excision, depending on the size, location, and characteristics of the nodule.